Liquid crystal displays (LCDs) are commonly used laptop computers, desktop monitors, television, as well as smaller applications such as in cell phones, personal digital assistants (PDAs), portable music players. Transmissive LCDs require backlighting, which is conventionally accomplished by illuminating the edge of the waveguide using a light source, such as LEDs.
Edge-lit backlights used in computer monitors and televisions have a minimum bezel-height and edge-thickness that is driven at least partly by the size of the light source and the waveguide thickness. FIGS. 1A and 1B, by way of example, illustrate a plan view and side view, respectively, of a conventional backlight 10 that includes an edge-lit waveguide 12 that is illuminated by a plurality of LED light sources 14, which are illustrated in FIG. 1B as including an LED 16 and reflector 18. As can be seen, the bezel height Hbezel is determined by the height of the LED light sources 14 and the thickness Tedge of the waveguide edge 12edge is determined by the width of the LED light sources 14. For aesthetics and design purposes, it is desirable to minimize the bezel height and edge thickness.